The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In general, a fuse box is installed in a vehicle. The fuse box normally contains a fuse to protect a circuit from power supplied to various electronic devices. Recently, a smart junction box (SJB) is prevalent as a multifunctional fuse box which contains a microcontroller unit (MCU) controlling an operational time of various relay circuits and other electronic devices, besides a general purpose of the fuse box.
FIG. 1 is a diagram illustrating an example of a general smart junction box 100.
Referring to FIG. 1, the smart junction box 100 may include an MCU 110 which controls in supplying or shutting off power to various loads in a vehicle. It triggers a relay and an intelligent power switch (IPS) with power supplied from a battery 210 based on a control signal received through a communication unit 220 and a state of a vehicle switch 230. In addition, the smart junction box 100 may normally include a fuse switch 120 that is turned on when a vehicle is delivered to a customer. As a result, the MCU 110 may control power supplied to the vehicle using different methods according to a state of the fuse switch 120, which will be described with reference to FIG. 2.
FIG. 2 is a flowchart illustrating an example of a procedure of managing vehicle power in a general smart junction box.
Referring to FIG. 2, as external switch input is generated or controller area network (CAN) communication is activated, the smart junction box may supply power to various load systems in a vehicle (S201). When a sleep mode condition is satisfied (e.g., CAN communication enters a sleep mode) after power is supplied (S202), the smart junction box may enter a sleep mode (S203) and perform an operation for shutting off dark current.
The operation for shutting off dark current may be varied according to a fuse switch state (S204). In detail, when the fuse switch is turned on at time of delivery to a customer, if a timer is started and a predetermined time (e.g., 20 minutes) elapses (S205), a lamp load is first shut off (S206). However, when a longer time (e.g., 12 hours) elapses (S207), a body electrical load may be shut off (S208). When the body electrical load is shut off, the MCU is powered off (S209) and is maintained in a corresponding state until a preset release condition is satisfied (S210). Here, when a lock signal is received through a remote controller such as a smart key after the timer is started, a short time (e.g., 5 seconds) elapses and, then, a load may be shut off. In addition, the preset release condition may be such as a change in exchange switch input and/or CAN communication activation.
When a fuse switch state is off, if a predetermined time (e.g., 5 minutes) elapses after the timer is started (S211), all loads may be shut off at one time (S222).
However, in the aforementioned power management apparatus, only some loads (i.e., lamp load and body load) are structurally shut off by a smart junction box. Also, a dark current blocking function is activated only per management policies of a vehicle manufacturer. As a result, it may be difficult to satisfy driver requirements.
In addition, determining whether a power system of a driving vehicle is abnormal is conducted for each load and, thus, the number of resistors required by a circuit for detecting and monitoring abnormal power may increase, thereby increasing manufacturing costs as well.